Hi, I would not worry. I'm 27 with CF and my liver enzymes have been elevated my whole life. I was extremely healthy as a child and never had any issues with CF until I turned about 15 or 16. The key to staying healthy is exercise. Loosening the secretions in the lungs so he can get rid of the mucus. He is very young right now so there wont be much mucus but keeping him active now will keep him active when he is older. Make sure he stays on top of his treatments, nebulizer physio etc. That will keep him healthy. I agree with your sister, day by day keeps one sane. Don't over do it...I don't even think about having CF so the more you think about it, the more of a burden you're putting on your sister and soon enough your nephew. I hope this all helps! Technology is ever changing! Your nephew has a long life ahead of him. If he does get sick, don't worry there is a ton of options available to make sure he gets happy and healthy again. Good luck